HDZero video link setup (VTX ↔ goggles)

Summary¶

HDZero is a one-way (simplex) digital video link — the goggles only receive, nothing goes back to the VTX. There's no bind or pairing step the way there is for a radio control link. What actually has to line up is firmware version between VTX and goggles, and band/channel between the two. Generic — applies to any HDZero VTX and goggle pairing, regardless of frame, flight controller, or firmware.

Concept¶

Why there's no "binding" step¶

A bind procedure exists for links that need to establish a specific transmitter-to-receiver relationship (like ELRS, where the receiver has to know which transmitter's packets to trust). HDZero has no return channel and no need to reject other transmitters' signals in that sense — the goggles just tune to whatever's on the channel they're set to, the same way an analog FPV receiver does. The "pairing" is really just "both ends agreed on a channel," which is a settings match, not a cryptographic or protocol-level handshake.

Why firmware version mismatch is the most common failure¶

The VTX and goggles negotiate the actual video encoding between themselves at the protocol level, and that protocol has changed across HDZero firmware releases. A VTX on one firmware version and goggles on a meaningfully older or newer version can fail to produce a picture even though the RF link itself is fine — this shows up as "solid red light, no picture," which looks like a hardware fault but usually isn't one.

Reference¶

Ways to reach the VTX's own menu¶

• Through the flight controller, via the same UART wired for OSD (OSD_TYPE = 5 / MSP DisplayPort on ArduPilot) — the VTX menu is reached with a stick gesture on the transmitter. The exact stick combo is firmware-version-dependent — check the current HDZero VTX manual rather than an older guide, since it has changed across releases.
• Via the VTX's own small keypad connector, if it has one — useful as a bench fallback when the FC isn't wired up yet, but the connector is delicate and not meant for routine field use.

Procedure¶

First-time setup¶

1. Update both the VTX and the goggles to the same current HDZero firmware revision before doing anything else. This is the step most likely to be skipped and most likely to cause a "no picture" symptom later.
2. On the VTX, set a band and channel via whichever menu-access method is available (FC stick gesture or keypad).
3. On the goggles, either let them auto-scan for an active HDZero signal, or dial in the same band/channel manually.
4. Confirm picture. If nothing appears:
5. Re-check the camera and MIPI cable are seated — the signal chain is camera → MIPI → VTX → (air) → goggles, and a break anywhere in that chain gives the same "no picture" symptom as a VTX or goggle fault.
6. Re-check firmware versions actually match, not just "both updated recently."
7. Re-check band/channel actually match on both ends.

Rationale¶

Framing this as "not a bind procedure" rather than teaching it as one is deliberate — a builder coming from ELRS naturally expects a pairing step for any RF link, and hunting for one that doesn't exist wastes time and risks "fixing" a channel mismatch by repeatedly power-cycling instead of checking the two things that actually matter: firmware and channel.

Connections¶

requires: [] related: - digital-fpv leads_to: - ardupilot-commissioning